84conversion50

well after i finally get the bolt i need and put the car back together. it backfires through the carb like crazy.... so i thought the intake valves were to tight and not closing but it still did it.

psyche116

double check your timing

84conversion50

i checked it like a thousand times.....

Boss_Hotrod

Did you check the firing order? Usually when it does something like that its because your 180* out.

84conversion50

its in the non HO order right now. when i put it into HO order it wont start.

67mustang302

Ignition timing or accelerator pump if everything else is ok. Have you tried changing the link on the pump arm for the carb to deliver more fuel?

84conversion50

no i dont even know what the accelerator pump is.

84conversion50

ok does an edelbrock 4bl carb have a power valve? it mainly only backfires when its in its secondarys.

mjr46

have you done a compression test???? low compression on more than one cylinder will cause incomplete cumbustion and cause backfires out the tail pipe.....my friend has a 77 ford that does that right now!! but I know you say out the carb so do a compression test!! a burnt intake valve can cause the same thing which will show up on a compression test and if such is the case you may have a slightly rough idle too???

84conversion50

it has a burnt exhaust valve in cylinder 8 all the other valves are fine for the time being. it holds a solid 120 in all the other cylinders except 8 which has 30lbs of compression